Lift truck



Aug. 4, 1936-. E s, FROST 2,050,000

' l' LIFT TRUCK v Filed June 4, 1954 2 sheets-sheet 2 Patented Aug. 4,1936 i'rED WT TUEX Elmer S. Fr d, Galli.

Application re e, rase,

sa o

This invention relates to a truck designed prioperated easily for thepurpose of lifting a loadand for lowering the same.

A still further-object is to provide a device or this character whichpermits the supported object to be rotated to any desired position whilesupported, there being a lock' for preventing this rotation whendesired.

With the foregoing and other objects in View which will appear as thedescription proceeds, the invention consists of certain novel details ofconstruction and combinations of parts .hereinafter more fully describedand pointed out in 'the claims, it being understood that changes `may bemade in the construction and-arrange-- ment of parts without departingfrom the spirit of the invention as claimed.

` In the accompanying drawings the preferred form of the invention hasbeen shown.y

In said drawings 2;, Figure vl is a side elevation of the completetruck.

' Figure 2 is a plan view thereof, a portion of the top being brokenaway.

Figure 3 is an enlarged section through the jack. g

Referring to the figures by characters of reference i designates asuitable base mounted on casters 2 or other supports whereby it can bemoved readily from place to place.

l Secured on the base, is the base block 3 of the back portion ofthetruck. |This block has a large boss i extending upwardly therefrom intoa tubular standard 5 to which it-can be secured by means of screwthreads as shown at t.

A yscrew threaded recess l is formed in the boss i at the center thereofand secured therein is the lower end of a cylinder t. `'l'hus an annularcompartment 9 is formed around the cyl y inder t and within standard Eand constitutes a eine. 729,012

to hold the standard 5 flxedly in upstanding position relative to block3 and base i.

Formed within the block 3 at a point outside of the standard b is athreaded recess id in which is secured the 'lower end' of thecylindrical 5 casing il of a plunger ib forming a force-pump. Thisplunger is mounted for reciprocation within its casing and is adapted tobe actuated l 'I by a handlever i9 one end of which is pivotally mountedon a supporting bracket t@ while lo intermediate portion is pivotallyconnected, as at 2i', to the' plunger i8. i

Extending downwardly within block Si from the recess i'is'a passage 2iintersected by an upper return passage 22 and a lower out-how l5 passage23. .The out-flow passage 23 opens into the recess 'i as shown at 2dwhile the return passage 22 opens upwardly into the reservoir d as shownat 25.

Passage 22 has a valve seat i6. A check valve 2a preferably comprising aball 2l engaged by a spring 2h is yheld normally against seat 2d so asto prevent the ilow o fluid from casingi'i and passage 2i into reservoirSi.

Passage 2i is provided with a valve seat 29 25 normally engaged by acheck. valve which, in the structure shown, comprises a ball 3d held toits seat by a spring' 3i. Thus this valve will act to open under thepressure of fluid being forced into passage 2i from casing ill but t0 30close under backward pressure from recess l and cylinder il.

A bypass connects the passages 22 and 23' and is normally,closed by avalve dit. This valve has a long stern ad extending outwardly from 35the block. 3 andprovided with a handle, foot lever or the like shown at35 whereby the valve can be turned readily to open or close the bypass.

A rotatable shank il@ is mounted to slide. within the cylinder d and hasits lower portion i0 enlarged as at di to form a piston. To the upperend oi this shank is securely fastened the top @e of the jack and tothis top is pivotally connected a spring-pressed dog'. te adapted to beseated in any .one of the notches i3 so as to hold the 45 shanlr 3d andtop t3 against rotation. This dog is of sumcient length to remain inengagement with a notch while the shank @e is being moved upwardly vordownwardly as hereinafter -explained. A It is to im understood thatreservoir 9 is to be partly filled with a suitable fluid such as oiland, in order to prevent the creation of` a vacuum within the reservoir,vent tubes t0 can be.sup' ported within the upper portion ot thereservoir,

eachot these tubes having openings I for permitting the ilow or air intoor out of the reservoir. f

If it is desired to lift a. stove or other heavy object, the truck ismoved to position thereunder with the top 38 in its lowermost position.The lever I9 is then actuated to reciprocate vplunger I8. During eachupward stroke of the plunger ou win be sucked into the casing l1 by wayof passage 22 at which time valve 2 1 will open and valve 3U will remainclosed. During each downward stroke of the plunger, valve 21 will closeand valve 30 will open. Thus the oil forced out of the casing I1 by thedescending plunger will ow into passage 2! and thence to passage' 23from which it will enter cylinder l beneath piston 31 and cause theshank 36 and the load thereon to move upwardly. As valve 30 will preventreturn ilow of the liquid, theel'evated parts will be held againstmovement downwardly when the pumping action is discontinued. The

truck with the load thereon can then be moved to any point desired, itbeing understood that the dog 39 will prevent the load from turning.

Thereafter the dog can be disengaged from the* notched head and the to'p31 rotated to bring the stoveor other object into proper position to belowered. By now opening valve 33 the liquid under the piston 31 will befree to flow through bypass 32 into passage 22 and thence back. to thereservoir where it will be stored for further use. As the iluid thusescapes to the reservoir the load'will be gently lowered into positionand thereafter the truck can be withdrawn. 4

What is claimed is:

1. In a lift truck, a Wheel supported base, an upstanding cylinderthereon, a piston slidable and rotatable in the cylinder and having ashank extending upwardly from said cylinder, a load engaging element atthe top of the shank and rotatable with the shank and piston, means forelevating the piston and shank relative to the cylinder, an annular headon the cylinder, a member pivotally suspended from the load en- 5 gagingelement, said member being adapted to slidably engage the head duringthe sliding movement of the shank, said head having means forcooperating with said member for holding the shank and load engagingelement against rotation relative to the cylinder after therotation ofsaid shank and element to certain predetermined positions. v

2. A lift truck including a wheel supported base, a cylinder mountedthereon including' a 15 cylinder and a shank slidably and rotatablymounted within and above the cylinder, an annular head on the cylinder,a, load engaging .element movable with the shank, and spring pressedmeans extending from the said element for slid- 20 ably engaging saidhead and for holding said element and shank against rotation after theirrotation to any one of a series of predetermined positions.

3. A truck including a base, an upstanding 25 cylinder thereon, aslidable and rotatable shank guided and surrounded by the cylinder, aloadengaging element at the top of the shank adjustable angularly withthe shank to any one of a plurality of predetermined positions, andcooperating means on said element and the cylinder for holding saidelement against rotation after annular adjustment to a selected positionwithout interfering with its reciprocation, said means including a headxed to the cylinder 35 and having a series of notches in its periphery,and an elongated dog depending from the loadengagingwelement andslidable within one of the notches during the reciprocation of theshank.

I ELMER S. FROST. 40

